Volume 36, Issue 1, 2017

Speedy bat smashes record

Brazilian free-tailed bats are faster than any bird in level flight


Bat flying in the sky
The Mexican free-tailed bat (Tararida brasiliensis mexicana) is a
subspecies of the Brazilian free-tailed bat and is found in the
southwstern United States and Mexico
Courtesy of Michael Durham

A new study published in the Royal Society Open Science reports that Brazilian free-tailed bats (Tadarida brasiliensis) may achieve speeds of up to 160 km/h (99.42 mph) in level flight.

This ranks this species of bat faster than any previously documented bird or bat in level flight.

This may be due to the Brazilian free-tailed bat’s aerodynamic body shape and longer-than-average wingspan in comparison to other bat species. This species of bat also appears to flap in a similar manner to ultrafast birds—punctuating moderate flight speeds with rapid bouts of fast flight. This is similar to the previous record holder, the common swift (Apus apus), which can reach speeds around 112km/h (69.7 mph).

Gary McCracken of the University of Tennessee in Knoxville (and BCI trustee) and colleagues at the Max Planck Institute for Ornithology used an airplane tracking method to document moderate flight speeds of the Brazilian free-tailed bats, and observed bouts of very rapid flight.

A small radio transmitter was attached to the backs of the bats and was tracked using a mobile receiver on a small aircraft. The scientists also evaluated data from nearby weather stations to note wind conditions at the time of the studied flights.

While this is the latest surprise bats have given researchers, it is most likely not the last. The mystery of bats still has many chapters yet to unfold, and who knows what else is out there to discover about these elusive mammals!

**Note: The Brazilian free-tailed bat is also known as the Mexican free-tailed bat in Mexico and the southern United States. So our bats at Bracken Cave are speedy bats!

All articles in this issue: